So here is the deal……..I’m building a small grow box that will be kept in my un-heated garage. In my neck of the woods, the fall and winter get pretty cold, often below freezing. During vegetative growth, the lights should keep the plants warm. However, once I go to 12/12 to flower, I’m concerned about the colder temps when the lights are off. Any suggestions on how to keep things warm in the grow box while the lights are off? Thanks in advance.

a heater...

yup thats the trick,or devide the shed two lights opposite times.two grows.say two 600 devided by panda plastic.if your going to have to run a heater you might as well use light for heat

You know man, during the flowering stage you need 12hours of darkness!

i think he means to divide it and have two areas with the light on at different times, so that the lights would be producing heat but the panda plastic will stop the light from leaking. Personally i think that might end up being a pain in the ass though.

if you're building a box and leaving it in an unheated garage during winter, you will still have temp. problems if you have proper ventillation set up. you would still need to draw in fresh air from outside the box, which would lower temps. inside regardless of what lights you have in there. you should definitely consider some kind of heater. and don't put your grow box on the concrete, as this will not help keep things warm either.

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my grow is very similar. I have a 8'x4' by 8' tall grow room in my garage. Room is pushing 100 F right now, because the light is on till noon, and at 4 a.m it was 85 F. I know its about 95 F outside right now. It's only 11:30 a.m right now. N E WAYS I plan on using a kerosene heater this winter, and will also put a piece carpet down for my resevoir to set on.
This was recommended to me as opposed to electric heaters, which are a larger fire risk in a unoccupied(except for your plants of course) room. Also kerosene burning releases carbon dioxide for your plants.
hope this helps.


I'msostonedagain

I'm thinking about using a heated seedling mat, with a thermosatic control, under my pots. With the use of a timer, the seedling mat will start once the lights go off. Do you think this would cause any problems with the plants?

if i remember corectly i think propane gives off much more co2 then karosene,but i may be wrong.

Dont forget about carbon monoxide either.